Newly reported laboratory results suggest that certain naturally-occurring immune system cells could one day serve as a treatment for multiple myeloma.

The results also suggest that therapies based on these cells may be made more effective when combined with a drug already used to treat myeloma.

Invariant natural killer T cells – or “iNKT" cells – are antitumor immune system cells. In multiple myeloma patients, iNKT cells are often defective or in short supply.

Researchers affiliated with Harvard University decided to test whether iNKT cells display antitumor activity against multiple myeloma.  They therefore collected healthy iNKT cells from a number of newly diagnosed and advanced multiple myeloma patients.

In laboratory tests, the researchers found that these iNKT cells showed a range of different antitumor responses to multiple myeloma cells.

In addition, the scientists found that the drug Revlimid (lenalidomide) enhanced both the development of iNKT cells and the ability of iNKT cells to destroy multiple myeloma cells.

Revlimid is already an approved treatment for multiple myeloma in patients who have received at least one prior therapy.  Some studies have shown that Revlimid enhances the general efficacy of iNKT cells.

Based on their results, the Harvard researchers conclude that iNKT cells, alone and in combination with Revlimid, show promise as a myeloma treatment.

The researchers report their findings in the November 1, 2008 issue of Clinical Cancer Research (article abstract).